1. Field of the Invention
The present invention relates to an apparatus and method for charging in a portable terminal. More particularly, the present invention relates to an apparatus and method for, when a portable terminal with a solar cell charges a battery by a solar light while the portable terminal is powered off, preventing the shortening of a battery lifetime that can take place as a charging temperature of a battery cell increases.
2. Description of the Related Art
In recent years, the use of portable terminals is increasing due to the convenience they provide. Accordingly, service providers (i.e., system manufacturers) are competitively developing portable terminals having more convenient functions to increase their user base.
For example, portable terminals are providing functions of a phone book, a game, a scheduler, a Short Message Service (SMS), a Multimedia Message Service (MMS), a Broadcast Message Service (BMS), an Internet service, an Electronic mail (e) mail service, a wake-up call, a Motion Picture Expert Group (MPEG)-1 or MPEG-2 Audio Layer-3 (MP3) player, a digital camera, and other similar products and services.
In order to provide mobility, portable terminals make use of chargeable batteries as a power supply. Since the chargeable battery is limited in capacity, if the use of the portable terminal increases, a battery consumption time is shortened. This creates an issue in that users have to determine a State Of Charge (SOC) of the chargeable battery for a long travel or outing, and have to charge the chargeable battery by supplying an external power source to the chargeable battery.
In order to address the above issues, portable terminals having solar cells are being introduced that employ solar power to charge the battery.
Portable terminals with solar cells can discontinue a charging function depending on a charging temperature of a battery cell while charging a battery using solar power. This prevents reductions in the useful lifetime and damage to the battery cell resulting from continuous charging using solar power.
However, portable terminals can control an operation of the charging function through the above function only while powered on. When the portable terminal performs a process of charging using solar power while powered off, the portable terminal cannot control the charging function because the portable terminal cannot sense the charging temperature of the battery cell while the portable terminal is powered off. As a result, when the portable terminal performs a continuous charging process via solar power while powered off, the battery may be damaged and its useful life reduced.